You "win" Leftist virtue signalling by being the more extreme and "self abasing". So advocating having serious, murderous, rapist enemies around makes these people the tops in their eyes. They figure they'll also never have to seriously interact with the new immigrants and so will be safe. They know they're evil pieces of *hit but can use it to raise their ranks among their fellow Leftists. Never forget Leftist are not just crazy, but EVIL.